Background and definitions: Animal-assisted therapy (AAI) is a complementary treatment modality with roots back to ancient Greece (1). It involves a patient, a highly trained animal, either a therapist, an experienced handler, or a volunteer, and a specific therapeutic outcome. The umbrella term AAI (known colloquially as “pet therapy”) includes both Animal Assisted Therapy (AAT) and Animal-Assisted Activities (AAAs) (2). AAAs in contrast to AAT are usually spontaneous, often involve the patient’s own pet and do not include specific treatment goals. This Fast Fact will highlight the value and clarify the details of AAT in the care of patients with serious illness.

Practical details: While many animals can be utilized in AAT, dogs and horses are most common due to their training and their ability to bond with humans (3). In healthcare settings, dogs are the preferred animal of choice (3,4). Certifications for the animal, therapist, or handler in AAT are typically obtained through one of hundreds of recognized therapy dog programs, such as Pet Partners (6). Depending on the clinical setting, a clinician may refer directly through their institution or externally through a certified pet therapy organization, licensed therapist, hospital, or rehabilitation center that offers AAT. Patients of nearly all ages and pathologies can access AAT. It has been facilitated in emergency departments, clinics, medicine wards, nursing homes, rehabilitation centers, and private residences (5,6). AAT sessions typically consist of facilitated patient-trained animal interactions, which vary from observing, talking to, or providing instructions to the animal, to walking, petting, grooming, or playing with the animal. Of note, equipping an animal with commercially available professional equipment such as a harness, by itself, does not qualify that animal to be service-eligible.

What are the benefits of AAT? The therapeutic rationale of AAT is based in attachment theory, where the animal is a substitute for a caregiver (7-9). Since a person’s relationship with an animal often involves tenderness, warmth, stability, and loyalty, feelings of unconditional love often emerge. These feelings foster comfort, acceptance, and reassurance during difficult times (9). There have not been many randomized controlled trials (RCTs) of AAT and there are methodologic challenges in blinding AAT, still notable trends in the published data have emerged: 

• In a study of hospitalized patients with cancer, AAT temporarily reduced depressive symptoms and increased arterial oxygen saturation when administered during chemotherapy treatments (10).
• In a nonblinded RCT of children with advanced malignancy who received AAT during oncology clinic appointments or hospitalizations, AAT reduced caregivers’ anxiety for up to 12 weeks (11).
• AAT reduced self-reported pain, depression, and emotional distress among patients seen at a cancer pain clinic compared to the typical waiting room experiences in a nonrandomized pilot study (12).
• AAT promoted positive effects on stress levels of health care team members caring for patients with life-limiting illness based on a case series (13).
• In a qualitative pilot study involving a group of children with autism, developmental delay, or a serious illness who were preparing to undergo a MRI, AAT reduced anxiety based on patient surveys performed shortly after the intervention (14).
• Five RCTs and five non-randomized controlled trials involving 413 total participants found that AAT resulted in fewer behavioral and psychological manifestations of depression and agitation among patients with dementia (15).

Risks and contraindications:  Adverse effects from AAT are uncommon and include allergies, infections (zoonosis and methicillin resistant staphylococcus aureus), and animal-related accidents like bites or scratches. Contraindications include allergy to the therapy animal, severe immunocompromised state, history of animal-related PTSD, history of aggression to animals, and open wounds or unprotected lines/catheters in the patient (9).

Cost considerations and barriers to implementation:  Insurance typically does not cover AAT; some insurers may cover services under complementary healthcare, but this usually requires a prior authorization. Out of pocket expenses range from $100 to $300 or more per session (16).  Select healthcare organizations and hospice agencies may subsidize the cost of AAT and provide treatment without additional charges. Still, variable coverage and an overall lack of regulatory oversight of the “therapy animal” industry continue to pose significant clinical implementation challenges for AAT.

Summary: AAT is an effective and well tolerated complementary modality in all palliative care patients, especially for patients with anxiety, depression, pain, developmental delays, or cognitive impairments.

References 

1. Fung A, Mok P, Fung Wing. The Rich History and Evolution of Animal-Assisted Therapy. J Altern Complement Integr Med 2024, 10:443. doi: 10.24966/ACIM-7562/100443.
2. Jones MG, Rice SM, Cotton SM. Incorporating animal-assisted therapy in mental health treatments for adolescents: A systematic review of canine assisted psychotherapy. PLoS One. 2019;14(1):e0210761. Published 2019 Jan 17. doi:10.1371/journal.pone.0210761.
3. Pandey RP, Himanshu, Gunjan, et al. The Role of Animal-Assisted Therapy in Enhancing Patients’ Well-Being: Systematic Study of the Qualitative and Quantitative Evidence. JMIRx Med. 2024;5:e51787. Published 2024 Mar 18. doi:10.2196/51787.
4. Gillett J, Weldrick R (2014). Effectiveness of psychiatric service dogs in the treatment of post-traumatic stress disorder among veterans. Hamilton, ON: McMaster University.
5. Serpell JA, Kruger KA, Freeman LM, et al. Current Standards and Practices Within the Therapy Dog Industry: Results of a Representative Survey of United States Therapy Dog Organizations. Front Vet Sci. 2020; 7:35. Published 2020 Feb 7. doi:10.3389/fvets.2020.00035.
6. Fick KM. The influence of an animal on social interactions of nursing home residents in a group setting. Am J Occup Ther. 1993;47(6):529-534. doi:10.5014/ajot.47.6.529.
7. MacDonald JM, Barrett D. Companion animals and well-being in palliative care nursing: a literature review. J Clin Nurs. 2016;25(3-4):300-310. doi:10.1111/jocn.13022.
8. Sable P. Pets, attachment, and well-being across the life cycle. Soc Work. 1995;40(3):334-41.
9. Bert F, Gualano MR, Camussi E, et al. Animal assisted intervention: A systematic review of benefits and risks. Eur J Integr Med. 2016;8(5):695-706. doi:10.1016/j.eujim.2016.05.005.
10. Orlandi M, Trangeled K, Mambrini A, et al. Pet therapy effects on oncological day hospital patients undergoing chemotherapy treatment. Anticancer Res. 2007;27(6C):4301-4303.
11. Mahoney AB, Akard TF, Cowfer BA, Dietrich MS, Newton JL, Gilmer MJ. Impact of Animal-Assisted Interaction on Anxiety in Children With Advanced Cancer and Their Caregivers. J Palliat Med. 2024;27(1):75-82. doi:10.1089/jpm.2023.0091.
12. Silva Carvalho F, Carvalho S, Conde R, Esteves S. Cynotherapy in Cancer Pain Management: A Pilot Study. Pain Med. 2021;22(12):3051-3061. doi:10.1093/pm/pnab118.
13. Engelman SR. Palliative care and use of animal-assisted therapy. Omega (Westport). 2013;67(1-2):63-67. doi:10.2190/OM.67.1-2.g.
14. Perez M, Cuscaden C, Somers JF, et al. Easing anxiety in preparation for pediatric magnetic resonance imaging: a pilot study using animal-assisted therapy. Pediatr Radiol. 2019;49(8):1000-1009. doi:10.1007/s00247-019-04407-3.
15. Hu M, Zhang P, Leng M, Li C, Chen L. Animal-assisted intervention for individuals with cognitive impairment: A meta-analysis of randomized controlled trials and quasi-randomized controlled trials. Psychiatry Res. 2018;260:418-427. doi:10.1016/j.psychres.2017.12.016.
16. PsychCentral website. Available at: https://psychcentral.com/health/animal-assisted-therapy#summary.  Last accessed April 17, 2025. 

Authors’ Affiliations: University of Texas Southwestern Medical Center, Dallas, TX.
Conflicts of Interest:  The author does not have any conflicts of interest to report.
Version History:  first published electronically in September 2025; originally edited by Sean Marks MD.